IIUC, the problem is a bit tautological. Regardless of legality of reverse engineering itself, HDMI is a trademark which you obviously cannot use without being licensed. Using HDMI connector itself is probably a grey-ish area: while you can buy the connectors without agreeing to any licenses and forwarding compliance on vendor, it would still be hard to argue that you had no idea it was a HDMI connector. If you are using the HDMI connector, but are not sending anything else but DVI over it, it should be fine-ish.

The real problem starts when you want to actually support HDMI 2.0 and 2.1 on top. Arguing that you have licenced for 2.0 and then tacked a clean-room implementation of 2.1 on top gets essentially impossible.

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johncolanduoni 2 days ago | parent | next [-]

For stuff like connectors, this gets worked around by using terminology like “compatible with HDMI” all the time. You are explicitly permitted to reference your competitor’s products, including potential compatibility, by trademark law. I suspect the risk here is mostly contractural - AMD likely signed agreements with the HDMI forum a long time ago that restrict their disclosure of details from the specification.

	▲	Xss3 2 days ago \| parent [-]
		Im shocked i had to scroll so far to find a real hard stop blocker mentioned. Valve has no reason to care about using the HDMI trademark. Consumers dont care if it says HDMI 2.1 or HMDI 2.1 Compatible. The connector isnt trademarked and neither is compatibility. The oss nature of isnt one either as valve could just release a compiled binary instead of open sourcing it. The 'get sued for copying the leak' argument implies someone would actually fancy going toe to toe with valves legal team which so far have rekt the eu, activision, riot games, microsoft, etc. in court. Proving beyond doubt that valve or their devs accessed the leaks would be hard. Especially if valve were clever from the get go, and lets face it, they probably were. Theyre easily one of the leanest, most profitable, and savviest software companies around.

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bobdvb 2 days ago | parent | prev | next [-]

HDMI's gate is certification and the ability to then use their marketing brand.

This is absolutely not a technical issue. You can implement the 2.1 spec if you want, you just can't say it's 2.1.

If Valve wanted they could happily get it to work and let people figure out that it works, they just can't use that title in their marketing.

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friendzis 2 days ago | parent [-]

IIUC the issue is not them being unable to implement 2.1 at all, but rather provide specifically open source implementation. They probably could provide a binary blob.

	▲	bobdvb 2 days ago \| parent [-]
		That's probably how NVidia did it. But there's very little software involved in HDMI, it's mostly hardware and a control API.

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crote 2 days ago | parent | prev | next [-]

The connector itself shouldn't be an issue, because it doesn't fall under IP. The shape of the connector is entirely functional, so there's no creative work involved, so it would fall under patent law. However, the connector itself is unlikely to be innovative enough to be patentable, so it's not protected by patent law either.

Using HDMI connectors is totally fine. You just can't label it as "has HDMI port", as "HDMI" is a trademark.

	▲	ukd1 2 days ago \| parent [-]
		Is that true? There is obviously some creative work in connector design - optimizing for looks, robustness to damage, dirt, easy of use, reliability technically, etc.

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grishka 2 days ago | parent | prev [-]

I've seen HDMI devices for sale on AliExpress that list their port as "HDMI-compatible" or just "HD" to avoid that certification requirement.